Ultrasound systems operable to provide images using transmission of ultrasonic energy are well known. Such systems typically employ a transducer assembly having an array of transducers where controlled excitation of the transducers causes an ultrasound wavefront to propagate into an adjacent medium, e.g., a human body. The ultrasound wavefront travels through the medium until reflected by an object or other variation in density of the medium experienced by the propagating wavefront. The ultrasound system uses the portion of the reflected ultrasound energy received by the array of transducers to process an image.
Beam forming techniques (e.g., providing relative phase and/or amplitude relationships) are typically used with respect to the transducers of the array of transducers in order to focus ultrasound energy when transmitting and/or receiving ultrasound energy. For example, different beam forming parameters, setting forth the phase and/or amplitude relationship for each transducer of the array of transducers to be used in forming the image, are used for each line (or ray) of an image frame. Additional information is generally used with respect to each such line, such as for image mode (echo, color, two dimensional, etcetera), image zone (focusing depth), image resolution (number of lines, line interleaving, line increments), and the like.
In the past, the foregoing beam forming parameters and additional information has been provided using a simple “brute force” technique. Specifically, a table having separate entries for each line of each frame would be provided. The entries for a particular line would include the beam forming parameters and additional information associated with that line of the frame. In forming an image frame, the ultrasound system would step through the table entries associated with a selected frame to obtain beam forming parameters and additional information for each line thereof. Accordingly, if a frame consists of 512 lines, 512 entries would be provided in the table for that frame, with each entry including all the beam forming parameters and additional information for the appropriate line. Additionally, each frame would have separate line entries for that frame, irrespective of whether any of that information was common to another line or frame.
Use of the above tables provides a straight forward technique for beam forming data control as each frame is expressly defined by a set of table entries. Accordingly, a new or different image mode, zone, or resolution may readily be implemented by a manufacturer of the ultrasound device providing table entries defining each line of a desired image. Moreover, providing control with respect to the beam forming data and additional data is very simple as the data entries for each line of a frame may be stepped through sequentially using common direct memory access (DMA) techniques.
However, the foregoing suffers from several disadvantages. For example, the use of separate entries for each line of a frame as provided in the past requires a large amount of memory to store beam forming parameters and additional information supporting various image modes, image zones, etcetera. Specifically, although some of the information, such as the image mode, image zone, image resolution, etcetera, may remain unchanged from line to line, the separate entries for each line of a frame as implemented in the past will discretely store such information for each line. Moreover, a first frame, such as may be associated with a first image mode, image zone, image resolution, etcetera, will have discrete entries associated with each line thereof, a second frame, such as may be associated with a second image mode, image zone, image resolution, etcetera, will have discrete entries associated with each line thereof, and so on. Accordingly, although some of the information, such as beam forming parameters, may be the same as between various lines of the frames, this information will be stored separately for each frame in which it is used.
From the above, it can be appreciated that techniques for beam forming data control implemented in the past require large amounts of memory. Such large amounts of memory can require relatively large amounts of space in an ultrasound system, can consume relatively large amounts of power to operate, and can generate relatively large amounts of heat to be dissipated by the ultrasound system. Such characteristics of large memories have typically not been an issue with respect to ultrasound systems as such systems are typically cart based configurations where size, power consumption, and thermal dissipation are not critical.